Testing schemes for physical network functions use dedicated testers to test appliances, which is expensive and time consuming. Moreover, these methods are unreliable as predictors for performance of virtualized network functions (VNFs) deployed on a Network Function Virtualization infrastructure (NFVI) due to constantly changing network conditions.
One of the inhibitors of virtual network function testing are the current methods of test case selection for pre-deployment and deployment testing. Since context of VNFs and network services (NSs) for testing vary, so do the applicable test cases. The certification context depends on a variety of factors.
For testing the VNFs, various users need to have a detailed understanding of the System Under Test (SUT) and the relevant test scenarios. For pre-deployment testing, the details of the VNFs have to be understood in order to be able to do acceptance testing, black box testing, performance testing, etc. For deployment testing, the details of the environment, in which the VNF is deployed, have to be understood. Moreover, VNFs in operation can be implemented on different NFVIs, so that the different instances of VNFs may require different test cases.
Since VNFs need to be deployed and replaced automatically, the testing of VNFs needs to be done in an automated way. Not knowing what test cases to perform exactly will lead to running all test cases, in order to be sure, rather than running only the relevant test cases.
The certification context is a set of metadata to drive the selection test cases and generation of test lists for a specific test demand within a predefined scenario (e.g., baseline certification, live network testing, service replacement and the like).
The certification context describes that part of a business process that should be tested. The certification context has many input artifacts and is a result of the integration planning or service design phase.
Currently, there are seven areas of certification identified. These seven areas cover all aspect of the certification context. The areas and the associated sources to generate a certification context are:
a) Infrastructure: HEAT Template to describe the infrastructure model of the VNF, (HEAT is the Openstack orchestration service; i.e., an open source infrastructure resource orchestration engine)
b) Package: VNF Package to describe the deployment and configuration model,
c) Baseline: Model for baseline testing (initial certification and conformance),
d) Service: Model for service layer certification,
e) Network: Model to describe the transport Internet Protocol (IP) core model of the connectivity,
f) Operational Support Systems/Business Support Systems (OSS/BSS): Model for OSS and Billing testing,
g) Performance: Model for performance benchmarking.
Note that the preceding list of areas and the associated sources a)-g) to generate a certification context are only examples for current key technologies in this area.